Faint Scrolling Lines

[Omegadsl]

I am using a PVR250 I can't figure out what's going on with it. This problem surfaced after a clean install of Windows XP. I've tried a number of things to get this resolved but to no avail.

My problem is that there are very faint lines scrolling through my video. At times they are difficult to see. However, they are always present. It's sorta looks like a too-slow refresh rate. These scrolling lines are recorded into the video. They appear when burnt to a DVD and played back on a TV. They are there when the video is played back on every computer I've tried.

Here's the stuff I've done in an effort to resolve this (none of this worked):

1). Changing the decoder in SageTV .

2). Changed the cable going to my digital cable box.

3). Changed my digital cable box.

4). Moved the card to another slot. I did this because it was sharing an IRQ. It is now in its own IRQ.

5). Changed desktop resolution, color depth, and refresh rate. I've tried just about every possible combination.

6). Tried a number of different drivers. I've found that the lines are more obvious on certain drivers.

7). Moved speakers away from PC to see if they were causing interference.

This is not a problem with SageTV. It's also present in WinTV2k. I am really at my wits end. Is it possible that something is wrong with my card? I've read about a problem with Hauppauge cards that sounded similar to this. It basically stated that Hauppauge cards tend to develop "scrolling lines" after a few months of use. I don't know if that is true or not because I read this on a random message board and haven't verified it elsewhere.

So, if anyone has some suggestions, I'd love to read them. Also, does anyone here know if Hauppauge is good with RMA's in the event that the card has gone bad? Thanks in advance.

[SHS]

Is there any way you can get screenshot so I my see what your seeing.

[Omegadsl]

I'll try to get a screenshot but I think it's probably going to be difficult to see. It's pretty obvious when it's moving, though.

[Omegadsl]

Okay, here's a screenshot. It was taken in WinTV2k (though the problem occurs in SageTV as well). I chose to take a screenshot of a still image because I thought it would be easier to see what I am describing. It's very faint in the screenshot, but I think you should be able to make it out.

http://members.bellatlantic.net/~alphadsl/Line1.jpg

[SHS]

Is this on all channel Omegadsl?.

[Omegadsl]

Originally posted by SHS
Is this on all channel Omegadsl?.

Yep, I just took a screenshot on that channel because I thought it might be easier to see against a still background.

[JJarmoc]

Could this be a groundloop issue?

[SHS]

Could be groundloop issue just wondering what input are you using

[Omegadsl]

Originally posted by SHS
Could be groundloop issue just wondering what input are you using

I'm using s-video. I tried composite but I got the same scrolling lines. I'll try to plug a TV in and see if the problem is before the PVR250. I don't think it is, though. I'll post back here tomorrow with the results :).

[Omegadsl]

I plugged a TV in and it seems that the problem is not with the source (no lines were visible on the TV). I was really hoping it was something like that :( . Does any one else have any suggestions? Also, does anyone know how Hauppauge is with RMA's (in case the card just went bad)?

[JJarmoc]

You may want to try plugging your PC and TV into seperate wall outlets as a test. It may or may not be practical to leave it like that permanently.

Also, this URL gives some information on what groundloops are and how to fix them.
http://documents.epanorama.net/documents/groundloop/video_isolation.html

I'm really just making a guesstimate here, but this sounds like the sort of thing that a groundloop could cause.

[Omegadsl]

Originally posted by JJarmoc
You may want to try plugging your PC and TV into seperate wall outlets as a test. It may or may not be practical to leave it like that permanently.

Also, this URL gives some information on what groundloops are and how to fix them.
http://documents.epanorama.net/documents/groundloop/video_isolation.html

I'm really just making a guesstimate here, but this sounds like the sort of thing that a groundloop could cause.

If it were a ground loop problem, wouldn't the bars be present if I plugged the TV directly into the digital cable box? That's what I did and they weren't visible. This makes me think that it's not a ground loop problem . I think the problem is after the box (i.e. the PVR250 card). Does that make sense?

[JJarmoc]

Well, it could be a groundloop where the PC is one of the devices causing it. If that's the case, and you remove the PC from the equation the loop would go away, which seems to be what you're seeing.

I may be wrong, but it's probably worth a shot before going to the trouble of returning the card.

[Omegadsl]

Originally posted by JJarmoc
Well, it could be a groundloop where the PC is one of the devices causing it. If that's the case, and you remove the PC from the equation the loop would go away, which seems to be what you're seeing.

I may be wrong, but it's probably worth a shot before going to the trouble of returning the card.

Ahh, that makes sense to me now :). I'll give it a try. Thank you for the suggestion.

[Omegadsl]

I tied pluging the devices into separate wall outlets. Unfortunately, it didn't work. I was really hoping it wasn't the card. Has anyone else ever seen these lines on their PVR250?

[ku71]

moving bars - it certainly sounds like a gound loop. They are usually caused by an electrical connection between the antenna ground (which is usually grounded in the literal ground nearby your house) and the AC ground, which has a different potential.

(not sure if I got the wording right, I never tried to describe a gound loop in english before :)

Ground loops are usually fixed by a passive DC/highpass filter for the TV cable. They come fairly cheap so this should be worth a try.

Martin

[Omegadsl]

Originally posted by ku71
moving bars - it certainly sounds like a gound loop. They are usually caused by an electrical connection between the antenna ground (which is usually grounded in the literal ground nearby your house) and the AC ground, which has a different potential.

(not sure if I got the wording right, I never tried to describe a gound loop in english before :)

Ground loops are usually fixed by a passive DC/highpass filter for the TV cable. They come fairly cheap so this should be worth a try.

Martin

I have determined that it is indeed a ground loop. Hopefully I will be able to fix it soon.

[JJarmoc]

Woohoo! Glad you've got it isolated.. How'd you finally confirm that's what it is?

[Omegadsl]

Originally posted by JJarmoc
Woohoo! Glad you've got it isolated.. How'd you finally confirm that's what it is?

I used a cheater plug (if that's the correct term) on the end of the power strip that all my devices plug into. When I did that, the bars went away. I'm not certain how I'll proceed from here. I'll probably end up buying something like this:

http://www.jensen-transformers.com/iso_vid.html

I was looking at the VRD-1FF listed on that page. I know there is a device that I can make myself (which would cost a lot less) but I'm concerned that the hit to signal quality might be too severe.

[ku71]

http://www.hut.fi/Misc/Electronics/circuits/antenna_isolator.html

[Omegadsl]

Originally posted by ku71
http://www.hut.fi/Misc/Electronics/circuits/antenna_isolator.html

Yeah, that's what I was talking about in my last post. The problem with that device is that it degrades the signal a bit. I'm probably going to see how it works before I buy the other one for $60.00 (which does not degrade the signal).

[Omegadsl]

Replacing the plug to my PC's power supply strangely cured the problem :eek:.

[ku71]

You may have found the other solution, disconnecting the ground from your PC equipment. This supposedly is a dangerous thing to do, if there is a defect and you touch the PC case, YOU are now the ground. I am not sure if you like being a conductor, but you certainly won't be for long :D